Bellows bonded at inner peripheral edges



United States Patent [1113,540,353

[ Inventors JeanLanglet, 511 lnt.Cl Fl6j3/00 Nellillysurseme; [50 FieldofSearch 92/34,45, Joseph Gustave Etienne Andre, Toulouse, 103M;103/l48; 73/410, 262;?4/13, 1 France 137/510; 29/454; 251 61, 335.2

21 AppLNo. 801,135

221 Filed Feb. 20, 1969 [56] References Cited Original application April4, 1966, Ser. No. UMTED STATES PATENTS 1,106,341 8/1914 Bristol 73 410[451 M74970 1 1,217,344 2/1917 Powers.. 92/45 [73]callismhcare'me'Francundsud' 1,570 861 1/1926 Quiroz 103/148 y'f 12,444,008 6/1948 Fentress 92/45 i 2,657,074 10/1953 Schwesteretal. 92 34Frenchcmnlmes 1 3,096,104 7/1963 Browning 92/45 [321 Pmmy AP'i'3J9653,422,680 1 1969 Nolte 92 34 [33] France [31 No, 11,854 PrimaryExaminer-Martin P. Schwadron Assistant Examiner- Leslie J. PayneAtlorneyMichael S. Striker ABSTRACT: A bellows in which a plurality ofthin-walled an- [54] BELLOWS BONDED AT INNER PERIPHERAL nular members ofsubstantially U-shaped cross section are ar- EDGES ranged axiallyaligned with each other in abutting relationship 4 Claims 3 Drawing Figsand bonded to each other at the inner peripheral edges [521 US. Cl 92/34thereof.

Patented Nov. W, 1970 FIG 2 F I G .l

fwd/urea:

Tame Mule? {@mgf" cal/AVE ETICMWIUIE mum/f f/m'ln' BELLOWS BONDED ATINNER PERIPHERAL EDGES CROSS REFERENCES TO RELATED APILICATIONS Thepresent application is a divisional application of the copendingapplication filed Apr. 4, I966 under the Ser. No. 539,780, now U.S. Pat.No. 3,442,005.

The present invention relates to bellows, and more particularly to abellows composed of a plurality of identical annular parts bondedtogether in a novel manner to withstand high temperatures and a highpressure.

Two basic types ofbellows are known in the art.

One type of bellows is known in which a thin-walled tube is corrugatedby a hydraulic process into a bellows. The alloys from which the thinwalled tubes are formed which are subsequently transformed into abellows necessarily have to have a ductility and stretchnbilitysufficient to sustain the considerable cold deformalion of the tube intoa bellows while maintaining after the formation acceptable mechanicalcharacteristics.

Therefore, only certain alloys such as tonibac, Monel or stainless steelmay be used for this purpose and none of these alloys is structurallyhardenable by heat treatment. Therefore the bellows produced from thesealloys are not adapted to resist at the same time high temperatures, ahigh pressure while being subjected to a corrosive atmosphere so as tooperate trouble-free for a considerable time under adverse operatingconditions. In addition, these bellows usually have a stroke less thanpercent of their free length and this stroke is preferably performed bycontraction ofthe bellows.

The second basic type of known bellows comprises a plurality of annulardisks welded at the inner and outer peripheral edges to each other.v Agreat number of metal alloys can be used for manufacturing a bellows ofthis type and especially alloys which can be structurally hardened byheat treatment may be used. The bellows of the second type willtherefore have mechanical characteristics improved over the bellows ofthe first mentioned type and the performance of the bellows of thesecond type will be superior in many respects with regard to the bellowsof the first type. Nevertheless, the welded portions of the second typeof bellows represent zones of fragility.

LII

For certain applications it is not necessary that the bellows can expandto a considerable extent in longitudinal direction or that they areflexible to a considerable extent in a direction transverse to theiraxes, but it is necessary that these bellows operate under severeoperating conditions, that is at high temperature, for example, at atemperature of 650 C. and that they have to withstand high pressuressuch as for instance 20 kg. per cm. In addition, the bellows in suchapplications may be subjected to strong internal turbulcnces andvibrations. The known bellows of the two constructions above mentionedwill go out of service under such operating conditions in a short timeeither due to rupture of the thin metal wall of the first mentioned typeof bellows or due to bursting of the bellows of the second type at thewelded edges thereof.

Various attempts have been made to overcome the shortcomings of the twotypes of bellows mentioned above, but the constructions known in the artto improve these bellows have not worked out satisfactorily in practice.

It is an object of the present invention to provide for a bellows whichavoids the shortcomings of the bellows known in the art mentionedbefore.

It is an additional object of the present invention to provide for abellows which is composed of a plurality of elements aligned along acommon axis, bonded together, and constructed and arranged in such amanner so as to withstand high pressure especially internal pressurewithout bursting.

SUMMARY OF THE INVENTION With these objects in view, the bellowsaccording to the present invention mainly comprises a plurality ofsuperintposed thin walled clements having surfaces of revolution andbeing aligned along a common axis with each other, each of the elementshaving in an axial cross section a substantially U- shaped configurationwith the concave side of said U-shaped cross section facing the commonaxis, wherein adjacent elements abut against each other and being bondedto each other along the inner peripheral edges thereof. The plurality ofelements above mentioned is preferably formed from sheet metal and theelements are bonded to each other preferably by welding along the innerperipheral edges thereof.

Preferably, the U-shaped cross section comprises a semicircular portionand a pair of substantially parallel leg portions tangential to saidsemicircular portion and projecting therefrom toward the axis of thebellows.

In such a construction, high internal pressure will not lead todestruction of the bond between adjacent elements since the higher theinternal pressure will he the higher will be the pressure at which theportions of adjacent elements which abut against each other are pressedagainst each other.

A bellows of the aforementioned kind can be manufactured from a greatvariety of alloys, especially from alloys which may be hardened by heattreating.

The bellows according to the present invention has a great numberofadvantages over the bellows according to the above discussed priorart. The bellows according to the present invention may be manufacturedfrom the plurality of superimposed toric shells in a very efficientmanner and therefore at reasonable cost. The bellows according to thepresent invention will have a movability in longitudinal and transversedirection which closely approaches that of the bellows of the firstmentioned kind. The shape of the bellows according to the presentinvention is especially adapted for the provision of internal orexternal guide means and means to prevent turbulence in the exterior ofthe bellows or vibration thereof. In addition, the bellows according tothe present invention has a remarkable resistance against high internalpressures even if applied under additional especially severe conditionssuch as temperatures higher than 650C. or maintenance of the bellows ina strongly corrosive atmosphere. Experience has shown that the bellowsaccording to the present invention will withstand such severe operatingconditions in a perfect manner.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are axial cross sectionsthrough bellows according to the prior art; and

FIG. 3 is an axial cross section through a bellows according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The bellows 1 shown in FIG. Iis a bellows according to the prior art in which a thin walled tube iscorrugated in a manner known to form the bellows I illustrated in FIG. Itherefrom. FIG. 2 likewise illustrates a bellows according to the priorart and the bellows 2 shown in FIG. 2 is composed ofa plurality ofsubstantially frustoeonical disks 3 which are welded at the inner andouter peripheral edges 4 and 5 to each other. Internal pressure in thebellows 2 will tend to spread the radially outwardly extending portionsof adjacent disks apart so that rupture along the outer edges 5 mayeasily occur.

FIG. 3 illustrates an axial cross section through a bellows according tothe present invention. As can be seen from FIG. 3 the bellows accordingto the present invention comprises a plurality of elements or shells 7wherein each of the shells 7 has a surface of revolution about the axisX-X which in an axial cross section has a substantially U-shapedconfiguration with the concave side of the U-shaped cross section facingthe aforementioned axis. More precisely each U-shapcd cross sectioncomprises a semicircular portion 8 and a pair of substantially parallelleg portions 9 tangential to the aforementioned semicircular portion andprojecting therefrom substantially normal to the axis X-X' towards thelatter. Each shell 7 is therefore substantially in the form of asemitore having a concave side facing the axis thereof and extendedtangentially by two flat annular portions The shells 7 are preferablymade from annular disks stamped out of sheet metal and the annular disksare then bent into the configuration as shown in FIG. 3.

After a plurality of shells 7 is manufactured, for instance in theabove-described manner, the shells are superimposed upon each other,aligned along a common axis, with the bottom portion of one shellabutting against the flat top portion of the shell adjacent thereto.Subsequently thereto the abutting portions of the shells are fixedlyconnected together for instance by autogenous welding in an inert gasatmosphere, for instance in an atmosphere of argon. The weld seams areproduced along the inner peripheries l ofthe shells.

In this way a bellows is produced which is adapted to withstand greatinterior pressure, since in the thus obtained construction an increasedpressure in the interior of the bel lows will press the leg portions 9of adjacent shells 7 with increased pressure against each other so thatthe weld seams 10 at the inner peripheries of the shells 7 will not beaffected by the increased pressure of the interior of the shells andevidently the bellows according to the present invention is adapted towithstand a much greater internal pressure than the bellows according tothe prior art as shown in FIG. 2 in which an increased interior pressurewill tend to press the outer peripheral portions of the frustoconicaldisks 3 away from each other so that the weld seams at the outerperiphery of these disks are liable to burst as the interior pressure inthe bellows increases.

To connect the bellows 6 shown in FIG. 3 to another machine element, anend member 11 as shown in FIG. 3 may be attached to the lowermost of theshells 7, for instance by welding the bottom portion of the lowermostshell 7 along the inner periphery thereof to the end member 11. A member12 having an upper cylindrical portion may be attached in the samemanner to the uppermost of the shells 7, as shown in FIG. 3. and themember 12 may serve to attach thereto in any convenient manner, forinstance likewise by welding, a connecting member not shown in FIG. 3thereto.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofbellows differing from the types described above.

While the invention has been illustrated and described as embodied in abellows formed by a plurality of substantially toric shells weldedtogether, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

For instance, if the bellows has to withstand an external pressure thetoric shells may be arranged so that the concave sides thereof face awayfrom the axis ofthe bellows.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

We claim:

1. A bellows adapted to be subjected to inner operating pressure andcomprising a plurality of one piece superimposed thin walled elementsdefined by surfaces of revolution, said elements being aligned along acommon axis, and each of said elements having in axial cross section asubstantially U-shaped configuration having a concave side facing saidaxis, said elements terminating in flat annular portions normal to saidaxis and having inner peripheral edges, the flat portions of adjacentelements abutting against each other and being bonded to each other andbeing bonded to each other along said inner peripheral edges, wherebyincrease of the inner operating pressure of the bellows will lead to anincrease of the cohesion of said elements, said bellows composed of saidU-shaped elements having a mobility in direction of said axis andtransverse thereto.

2. A bellows as set forth in claim I, wherein said elements are formedfrom sheet metal and wherein said elements are welded to each otheralong said inner peripheral edges thereof.

3. A bellows as set forth in claim 2, wherein said elements are formedfrom hardened sheet metal.

4. A bellows as set forth in claim 2, wherein said U-shaped crosssection comprises a semicircular portion and said flat portions forminga pair of substantially parallel leg portions tangential to saidsemicircular portion and projecting therefrom substantially normal tosaid axis towards the latter.

